Citrus flat-headed borer

The citrus flat-headed borer (Agrilus occipitalis) is a wood-boring beetle belonging to the Buprestidae family within the Coleoptera order. This pest is a significant threat to citrus production, known for its ability to damage the cambium layer of tree trunks and branches, leading to severe decline in affected orchards.

The pest primarily targets citrus species, including lemon, lime, and orange trees. While adult beetles may feed on leaves, the larval stage is the most destructive. Larvae bore into the bark and feed on the inner tissues, effectively girdling the branches and preventing the circulation of nutrients and water.

The life cycle of Agrilus occipitalis consists of four stages: egg, larva, pupa, and adult. The females oviposit on the bark surface. Upon hatching, the larvae immediately tunnel into the host plant. They spend the majority of their development cycle beneath the bark, creating winding galleries filled with frass, which disrupts the tree's physiological functions.

Symptoms of infestation include branch dieback, yellowing foliage, and stunted growth. A key diagnostic feature is the presence of D-shaped exit holes on the bark, which appear when the adult beetles emerge. Without intervention, severe infestations can lead to the death of the entire tree, as the structural and vascular integrity is compromised.

Effective management strategies require an integrated approach. Essential practices include the prompt removal and destruction of infested wood, maintaining optimal tree health through proper fertilization and irrigation, and the strategic application of systemic insecticides during the beetle's peak flight season. Early detection through regular orchard scouting is critical for minimizing economic losses.